1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.proxy2.invoker;
19
20 import java.io.Serializable;
21 import java.lang.reflect.Method;
22
23 import org.apache.commons.proxy2.Invoker;
24 import org.apache.commons.proxy2.ProxyUtils;
25
26 /**
27 * An {@link Invoker} implementation which merely returns null for all method invocations. This class is useful for
28 * scenarios where the "null object" design pattern is needed.
29 *
30 * @since 1.0
31 */
32 public class NullInvoker implements Invoker, Serializable
33 {
34 /** Serialization version */
35 private static final long serialVersionUID = 1L;
36
37 /**
38 * Statically available instance.
39 */
40 public static final NullInvoker INSTANCE = new NullInvoker();
41
42 //******************************************************************************************************************
43 // Invoker Implementation
44 //******************************************************************************************************************
45
46 /**
47 * {@inheritDoc}
48 */
49 @Override
50 public Object invoke(Object proxy, Method method, Object[] args) throws Throwable
51 {
52 final Class<?> returnType = method.getReturnType();
53 return ProxyUtils.nullValue(returnType);
54 }
55 }